Hydraulic brake



I March 13, 1945.` w. w. CARTER y HYDRAULIC BRAKE Filed July 1, 1944 2 sheets-sheet 1 W MW w M mw m ww WW., N f 0 W j u im wy i W/ 2- w m 3.

March 13, 1945.` W, w` CARTER Y 2,371,503

HYDRAULIC BRAKE Filed July 1, 1944 2 Sheets-Sheet 2 E E z E 1N: ENTOR. M7/mm M4 af/*er E Patented Mar. 13, 1945 UNITED STATES PATENT- OFFICE mimmo Bam wmnm w. can, mm city, M0. Application July-1, 1944. semi Na. 543,121 1o cam. (criss-ss) This invention relatesto hydraulic brake structureof the character adaptable for use on automobiles or the like, and has for its primary aim to provide effective, rugged and positively acting means for applying braking action to a movab1 e part when ythe specially designed, manually operable apparatus is actuated.

One of the primary aims of this invention is'the provision of hydraulic brake structure having as.

a component part thereof, a plurality of specially disposed brake-shoes, housed within a closed filled with liquid and longitudinally shiftable by manually operable apparatus to enga-ge the inner surfaces of the ends of the brake drum as radial, bodily shifting occurs to contribute toward a positive locking together of the said brake shoes and drum.

Other objects of the invention include the provislon'of a. plunger mounted upon the brake drum for radial movement as the brake shoes are radially shifted, as just above set forth, which plunger into a conventional brake for automobiles.

vnumeral lil designates a closed brake drum vis is adapted to receive the force of liquid within l the drum to a progressively greater degree as the brake shoes are shifted radially to have a relatively small portion of the outer faces thereof come into engagementwith a like portion of the inner face of the side wall of the brake drum. This invention has for a further 'aim the provision of a hydraulic brake structure having coopl l e-rating, closed liquid 4llled'brake drum and a pair of shiftable. brake shoes between which a segmental expansion ring is disposed, said ring being operably joined to manually controlled apparatus for forcing the expansion ring. between the brake shoes to thereby bring the edges of the brake shoes into frictional engagement with. the inner surfaces of theend walls of the brake drum.

Further important objects will appear during the course ofthe following specification, referring to the accompanying drawings, wherein.

Fig. 1 is a cross sectional view through the Sectional Fig. '4 is -an .enlarged fragmentary view taken on line ,IV- IV of Fig. 2.

Pig. 5 is a i'ragmentarysectionalview taken onV line V.-'V of.Fig. I1.

Fig. 6is a sectional view similar'to Fig. l, but showing the brake shoes radially shifted into contact with the brake drum: and

l hydraulic brakestructure embodying this inven- Fig. 7 vis an enlarged fragmentary cross sectional view taken on lin`e VII-VII of Fig. 2.

The 4illustrated embodiment of the invention shown in the accompanying drawings clariiies the manner in which the invention may be built The adapted to vbe mounted on a rotatable element such as the automobile wheel, nothere shown, through the medium of bolts or analogous means I2 The brake drum comprises flat end walls I4 and i6 respectively, and an annular side wall I 8. Wall viimaybe removably amxed in position by machine screws 20,for purpose of assembly, and the entire drum is mounted upon a stationary part generally designated by the numeral 22 and which is in itsspe'ciiic form an axle housing 24 about which may be-positioned a bushing 26 welded or otherwise fastened to axle housing 24. Friction bearings and an oil seal 28 and 3U respectively, circumscribe the stationary part 22 and insure free rotation by drum Ilthereabout.

Bushing 26 is polygonal in cross section as illustratedin Figs. 1 and 6, and carries a number of rollers 32 in grooves 34. This relatively station- .ary bushing 2B has a cylinder 36 secured thereto wherein is operably mounteda piston 38 joined to cross head 4 0 by 4rod 42'. Cylinder 36 is joined to conventional, manually operable apparatus by a tube 44 and passages 46. A retrieving spring 4B has one end attached to bushing 2C and the other end secured to cross head 40 for purposes more mllyhereinafter set down.

A pair ofv arms is arranged on each side` respectively of bushing 26. Arms liii' constitute a pairto one side of bushing 26, whilearms S2 are'on the opposite side of the-bushing. The 'ends of 'these arms are slidably tted into cavities 54 and 'Il formed in brake shoes Il and 60 respectively.

These shoes are annular and continuous. nThey are spaced apart as illustrated in Fig. 3, and the proximal edges 62 and i4 of brake shoes and ,I0 respectively, are inclined to present a wedge- 'shaped space between the said brake shoes intowhich is tted the segmental expansion-ring 86. Thisrlnglsintwosectionsandwhenthe partsof the brake drum structure are normal and not. applying braking force, brake shoes 58 and 6I arey concentric so far as wall I8 of drum il is con-v cerned, and the sections of expansion ring B6 have their ends spaced apart, as clearly shownin Fig. 1.l The outer edges of brake shoes Il and `Bil which are faced withleather or the like Il, are not againstthe end walls i4 and II of drum Il The sections of expansion ring E5 have heads l disposed therebetween. 'I'hese heads are inclined to be complementary to the angles of inclnation of the ends of segmental expansion ring S8; to the end that radial movement oi heads 10 will force the sections of expansion ring S6 Vapart and thereby into place between brake shoes 58 and- SB to expand the same. The proximal ends of the sections of expasnion ring SS are inclined to present a progressively increasing space as the axis of the brake is approached and heads 10 are engageable with the ends of the ring sections. f

Each head 1li is pivotally mounted on one free end of a bell-crank lever 12. lever is pivotally mounted as at 14 to arms 50 to one side of bushing 26. The other free ends of these bell-crank levers 12 have pins 15 that enter slots 18 in a pair of opposed ears 80 rigid to bushing 28. These slots 18 have an inclined Y lengthand a length parallel to arms D, and therefore, parallel to the path of travel of the arms when radial shifting -oi.' the parte occur as later set forth.

'Annuler side wall i8 of drum ill carries a plunger assembly indicated by the numeralA 82. and speciiically comprising a housing 84 having liquid passageways 85 wherein a pair oi valves B8 and 50 are disposed. These valves are yieldably supported and coupled as at 94 to move as a unit.

The plunger 92 per se, has a facing 95 of leather or similar substance, and is hollow as seen in Figs. l and '7. A pair of compression springs 98 exert a slight inward radial force upon plunger 52 to overcome any centrifugal action. Valve 83 allows the passage of liquid into plunger $2 when the` liquid is moving in the i direction of the arrow shown in Fig. 7, and valve 90 allows the entrance of liquid into plunger 92.-

when the liquid is moving through passageways 85 in the direction of the arrow shown in Fig..'7.

The valves 88 and!!! move against the adjacent face of housing 8l in the event liquid attempts to move past the respective valves in a direction .opposite to the arrows shown.

When hydraulic brake structure of the characterjust described and illustrated in the accompanving drawings is operated. the manually `controlled apparatus maybe oi a character different from the hydraulic type shown and including piston 38 and its containing cylinder 35 However, under the conditions here disclosed. the hydraulic brake system does include this said piston and cylinder. which is joined to a master reservoir, the pressure wherein is con- -trolled by a foot pedal or the like. Upon de- A pressing the foot pedalnthe oil in cylinder 3E moves piston 38 radially and in the direction shownby -the arrow in Fig. 1.

Such action bodiLv moves cross 5D and 52, bell-crank levers 12, heads 1B. `expension' ring 66. and annular brake shoes, and il Such movementis relative to bushing 2B and roller bearings 3 2 eliminate friction.

It is notable that drum i0 is completely illled with liquid and as such movement occurs. the space between the outer annular faces of brakel shoes B8 and 60 andthe inner annular face Vof side wall I8 of drum lli, app aches the-form shown in Fig.\6. Before this position is reached howevenbell-crank levers 'l2 have been shifted by the inclined portions of The elbow oi said ltimate lockingwhen the brake is in the position illustrated in Fig'. 1.

slots 18 in ears 8B and heads lil have been moved radially outwardly to increase the diameter of the wedge-shaped expansion ring Si to thereby force the same between the inclined proximal faces of brake shoes 58 and $9. ASuch action forces brake shoes 5o 'and Sil against the end walls It and I8 respectively of the brake drum to establish a braking action that is transmitted to the wheel upon which the brake drum is mounted by elements l2. It must be remembered that brake drum i is travelling with the wheel and that plunger 92 is serving to move the oil around the axis of the brake drum and in the space formed between the brake shoes and the annular wall of said drum.

"As pressure is applied to the manually operable f expansion ring 86. As the space between said brake shoes approaches that form shown in Fig. 6, the back pressure against plunger S2 becomes greater because ofthe restriction at the closed point between the brake shoes and the wall I8 of the brake drum.

Very line adjustment Aand e. light touch of the brake is all that is necessary to completely lock together the stationary parts 24 and and the movable parts constituting the drum and plunger 92. When the structure is in the condition illustrated in Fig. 6, oil is compressed and the plunger nor its supporting drum can no longer move. Progressively increasing force is applied to the face of plunger 92 to seal the joint between its face S8 andthe outer annular faces of brake shoes 58 and 89. This progressively increasing force is set up because oil passes into plunger 92 past valve 88 when the brake drum is moving in the direction of the arrow shown in Fig. 6, and thence into the plunger. Valve Sil is closed under these conditions.

From the foregoing it will be observed .that not only do brake shoes 58 and SB expand against the ends of the brake drum, but the body radial position.

Itis obvious from the foregoing that an exceptionally efiicient and rugged hydraulic brake head l0. arms structure has been provided to embody the concepts of this invention, and while one form has been illustrated and described. it is understood .that mcdineauons may be made without departing from the scope of the appended claims.

Having thus described the invention, what is claimed as new anddesired to be secured by Letters Patent is:V

v1. Hydraulic brake described comprising a drum adapted to be mounted on a rotatableelement to which brak-l ing action is to be applied; a stationary part extending-into the drum at its axis; a pair of brake shoes within the drum and mounted for longitudinalmovement toward andv from a position respectively against the end walls of said drum: and manually operable apparatus for moving the structin'e of -the characterA 2. Hydraulic brake structure of the character.

described comprising a drum adapted to be mounted on a rotatable element to which braking action is to be applied; a stationary part extending into the drum at its axis; a pair of 'brake shoes within the drum and mounted for longitudinal movement toward and-from a position respectively against the end walls of said drum and manually operable apparatus for moving the said brake shoes into frictional engagement with the end walls of the drum, said manually operable apparatus and the brake shoes being radially shlftable within the brake drum as the brake shoes4 are longitudinally lmoved toward the end walls of the drum, the inner face of the side wall of the drum being annular, the outer face ofthe brake shoes being annular with a portion thereof in contact with a portion of the inner face of the sidewall of the drum structureis fully set.

3. Hydraulic brake structure of the character described Acomprising a drum adapted to be mounted on a rotatable element to which braking action is to be applied;` a stationary part extending into the drum at its axis; apair of brake shoes within the drum and mounted for longitudinal movement toward and from a position respec-A tively against the end walls of said drum; and

manually operable apparatus for moving the said brake shoes into frlctional engagement with the end walls of the drum, said manually operable apparatus'and thebrake shoes being radially shiftable within the brake drum as the brake shoes are longitudinally moved toward the end walls of the drum, the 'inner face of the side wall of the drum being annular, the outer face of the brake shoes beingannular with a portion thereof in contact with a portion of the inner face of the side Wall of the drum when the brake structure is fully set, said drum having a plunger shiftably mounted thereon for radial movement toward the outer face of the brake shoes 4to one side of the portion thereof in contact with the side wall of the brake drum.

4. Hydraulic brake structure of the character described comprising a drum adapted to be mounted on a rotatable element to which braking action is to be applied; a stationary part extending into the drum at its axis; a pair lof brake shoes within-the drum and mounted for longitudinal movement toward and from a Aposition respectively against the end. walls lof said drum; and manually operable apparatus for moving the said brake shoes into frictional engagement with the end walls of the drum, saidmanually operable apparatusand the brake shoes being radiallyshiftable within the brake drum as the brake shoes are longitudinally moved toof the-side wall of the drum being annular, the outer face of the brake shoes being annular with a portion thereof in contact with a portion of the inner face of the side wall of the drum when the brake structure is fully set, said drum having a plunger shiftably mounted thereon for radial movement toward the outer face of the brake shoes to one side of theportion thereof in contact with the side wall of the brake drum, said brake drum having a iilling of liquid therein, the said plunger having means associated therewith for directing liquid radially and thereagainst when' the brake ment with the -end mentioned means ward the end walls of the drum, the inner face vmounted on a -from aposition in frictional when the shoes are against the said drum and the plunger is moved around the brake shoes by the said drum.

5. Hydraulic brake structure of the character described comprising a drum adapted to be mounted on a rotatable element to which brak- -sion ring being sectional .and wedge-shaped in transverse cross section, the manually operable apparatus including heads shiftably arranged for movement between the ends of the expansion ring sections to increase the diameter of the said ring.

6. Hydraulic brake structure ci the kind set forth in claim 5, wherein each head is carried by a lever having connection with the stationary vparl: and the brake shoes.

A'1. Hydraulic brake structure of the character f described comprising a drum adapted to be rotatable element to which braklng action is to be applied: a stationary part extending into the drum at `its axis; a' pair of annular, side-by-side brake shoesmounted onl the stationary part for longitudinal movement lto and engagement with the inner faces oi' the ends of the drum; an expansion ring between the said'- brake shoes: ra-

. dially shiftable arms supporting the brake shoes upon the stationaryI part and adapted to permit' said longitudinal movement: and means operable upon said radial Shifting of the the expansion ring between the pair of brake shoes to force the same into frictional'engagement with the end walls of the drinn.

8. Hydraulic brake structure of the character described comprising a drum adapted to be' mounted on a rotatable element to which braking action is to be applied; a stationary part ea,-

tending into the drum at its axisra pair of annular, side-by-side brake shoes mounted on the stationary part for longitudinal movement to and from a, position the inner faces of the ends of the drum; an e pansion ring between the said brake shoes; radially shiftable arms supporting the brake shoes upon the stationary part and adapted to permit said longitudinal movement; and means operable upon said radial shifting of the arms for forcing the expansion ringbetween the pair of brake shoes to force the same into frictionalengagewalls ofthe drum, said last being formed to force the expansion ring between the pair of brake shoes during a part of its radial path of travel as the said brake shoes, the expansion ring, and the said arms traveltogether and'to bodily movethe said brake shoes, the said expansion ring, and the said arms further toward the annular side wall of the drum without relatively moving the expansion ring and the brake shoes.

arms for, forcing in frictional engagement withv ment toward and? from the outer anner faces of the brake shoes: and manually operable apparatus for moving the brake shoes longitudinally against the ends of the brakedrum and simultaneously radially thereof, said plunger ,beingI contained in av. housing having' valved passageways formed to direct liquid against the plunger and force the same against the said brake shoes when the brake shoes have been radillyfshifted 

